Sarcoidosis

Correct Answer: C

Rationale: Sarcoidosis causes bilateral hilar lymphadenopathy (C) in 90% of cases. Choice A is false; its cause is unknown (possible immune dysregulation), not silica (pneumoconiosis). Choice B is incorrect; granulomas are non-caseating. Choice D is wrong; lung pathology is most common, followed by eye/skin lesions. Choice E (more in women) is true. Page 737 confirms C's radiographic hallmark hilar nodes distinguish it, unlike A's etiology or B's necrosis error.

Correct Answer: C

Rationale: Gram-negative rods are common nosocomial pneumonia pathogens (C), e.g., Klebsiella, Pseudomonas. Choice A is false; they're common with severe disease (e.g., intubation). Choice B is incorrect; antibiotics are a risk factor, not preventative. Choice D is wrong; Strep pneumoniae is minor in hospitals. Choice E (life-threatening) is true. Page 752 lists C's dominance gram-negative 'poo bugs' thrive in hospital settings, unlike A's broad claim or B's prevention error.

Correct Answer: A

Rationale: Goblet cells are specialized epithelial cells in mucous membranes, like those in the respiratory tract, that secrete mucus to trap pathogens and debris, protecting underlying tissues. Macrophages are immune cells that engulf pathogens, not mucus producers. Phagocytes, a broader immune cell category, also lack mucus-secreting roles. Ciliated epithelial cells move mucus via cilia but don't produce it working with goblet cells to clear airways. Goblet cells' mucus is vital for the mucociliary escalator, a defense mechanism in the lungs and nasal passages, where mucus captures particles and cilia sweep them out. This division of labor ensures respiratory surfaces stay moist and clean, preventing infection and irritation, a fundamental concept in understanding respiratory histology and immunity.

Correct Answer: D

Rationale: Syncytia are multinucleated cells formed by host cell fusion during viral infections like respiratory syncytial virus (RSV) or measles, where viral proteins (e.g., fusion proteins) merge cell membranes, aiding spread. Ghon elements relate to tuberculosis lesions, not fusion. Reye syndrome is a post-viral liver-brain condition, not cellular. Koplik's spots are measles' oral signs, not fused cells. Syncytia's formation reflects viral pathogenesis, visible in tissue cultures, and contributes to symptoms like airway damage in RSV. Understanding this term clarifies how viruses amplify infection, distinct from other disease markers, key in virology and respiratory pathology studies.

Correct Answer: B

Rationale: Rust-colored sputum (B) is expected in lobar pneumonia, typically from Streptococcus pneumoniae, as hemoptysis results from RBC breakdown in consolidated alveoli. Brown (A) suggests old blood or fungal infection (e.g., Aspergillus), not classic lobar. Red (C) indicates fresh bleeding, rare unless necrotizing. Cloudy (D) is purulent (e.g., bronchopneumonia), not specific to lobar's bloody hue. The document's answer (B) matches pathology S. pneumoniae's virulence causes capillary leakage, yielding 'rusty' sputum, a hallmark distinguishing it from A's chronicity or D's infection type.